Foldable chair frame

ABSTRACT

A foldable chair frame includes front leg rod units, rear leg rod units, cross-shaped long leg members, cross-shaped short leg members and movable armrest unit. The front leg rod unit includes a pair of front leg rod members, base caps, receiving caps and receiving cap base of the front leg. The rear leg rod unit includes a pair of rear leg rod members, base caps, receiving caps and receiving cap base of the rear leg. The cross-shaped long leg members and cross-shaped short leg members are in bar shape and have pin holes being installed respectively at the central part and each ends thereof. The movable armrest unit includes a pair of main shaft and fixing caps.

BACKGROUND OF THE PRESENT INVENTION

1. Field of the Invention

The present invention relates to a chair frame, particularly to across-shaped foldable chair frame.

2. Description of the Related Arts

As shown in FIG. 8, the conventional foldable chair is shown to comprisecrossed-shaped front, rear, left and right leg unit which are equal inlength. Therefore the shape is shown to be square when the chair iscompletely in unfolded position. However, people usually need largerfrontal than lateral space when seat on the chair in concern of beingergonomic, which means that when the frontal space is enlarged, thelateral space will also definitely be enlarged. Therefore, such designhas the disadvantages such as not being able to match the ergonomicproblem, wasting material and enhancing the cost.

SUMMARY OF THE PRESENT INVENTION

Please refer to FIGS. 1, 2, 3 and 4, the inventors has improved thedesign in view of the shortcomings of the prior art. The presentinvention is a new structure of cross-shaped foldable chair frame. Theadvantages are as following.

First, the present invention comprises leg units in different lengthwhich respectively form two X-shaped structures in different size andmake the whole chair frame structure be in rectangular shape and meetthe ergonomic standard.

Second, two opposite ends of left and right leg units are respectivelymounted to the receiving caps on the middle and upper parts of the frontand rear leg rods to keep the leg unit in X shape.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the present invention.

FIG. 2 is a perspective view of the preferred embodiment of the foldablechair frame according to the present invention.

FIG. 3 is a front view of the preferred embodiment of the foldable chairframe of the present invention.

FIG. 4 is a side view of the preferred embodiment of the foldable chairframe of the present invention.

FIG. 5 is a side view illustrating the action of folding the preferredembodiment.

FIG. 6 is the second example of the side view illustrating the action offolding the preferred embodiment.

FIG. 7 is the third example of the side elevation view illustrating theaction of folding the preferred embodiment.

FIG. 8 is a perspective view of a conventional foldable chair frame.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

Please refer to FIGS. 1 through 7, the preferred embodiment of thefoldable chair frame which is in rectangular shape when being unfoldedis shown to comprise rear rod units (10), front leg rod units (20),cross-shaped long leg members (30), cross-shaped short leg members (40)and movable armrest units (50).

The rear leg rod unit (10) comprises a pair of rear leg rod members(11), each of which is in cylinder shape, base caps (12), which arerespectively installed with a pivot bracket (121) for engaging with thecross-shaped long leg members (30), receiving caps (13) and receivingcap base of the rear legs (14). The receiving caps (13) which arerespectively installed with pivot brackets (131) for engaging withcross-shaped short leg member (40). The receiving cap bases of the rearlegs (14) which are respectively installed with a pivot bracket (141)for engaging with cross-shaped long leg members (30) and cross-shapedshort leg members (40).

The front leg rod unit (20) includes a pair of front leg rod members(21), each of which is in cylinder shape, the base caps (12), thereceiving caps (13), and the receiving cap bases of the front legs (22)which are respectively mounted on the front leg rod members (21) andinstalled with a pivot bracket (221), of which a cylinder sheath (222)extending from the bottom, for engaging with the cross-shaped long legmembers (30) and cross-shaped short leg members (40).

The cross-shaped long leg members (30) and the cross-shaped short legmembers (40) are respectively connected pivotally to each other via pinholes (301) which are installed at the end and middle of the leg membersto form into X shape. The cross-shaped long leg members (30) arerespectively installed between a pair of front leg rod units (20) and apair of rear leg rod units (10) forming the front and rear sides of thechair frame structure. The cross-shaped short leg members (40) arerespectively installed between a front leg rod unit (20) and a rear legrod unit (10) forming the right and left sides of the chair framestructure.

The movable armrest unit (50) includes a pair of main shafts (51) incylinder shape, and fixing caps (52). At one end of the main shaft (51)is installed with a protrusion (511) for engaging with the fixing cap(52), at another end of the main shaft (51) is installed with an end cap(512) which has a groove (513) inside for engaging with the front legrod member (21) when the frame is in the unfolded position and a fixingclip (514) extending from the bottom of the end cap (52) to clip withthe rear leg rod member (11) when the frame is in the folded position.The fixing cap (52) is engaged movably with the rear leg rod member (11)for the main shaft (51) being able to move around.

The preferred embodiment includes a pair of rear leg rod unit (10), apair of front leg rod unit (20), four cross-shaped long leg members(30), four cross-shaped short leg members (40) and a pair of movablearmrest units (50). The base cap (12) is installed at the bottom, thereceiving cap (13) is mounted on the middle portion and the receivingcap base (14) is then installed at the upper portion of the rear leg rodmember (11). Further more, the base cap (12) is installed on the bottom,the receiving cap (13) is mounted to the middle portion, and thereceiving cap base (22) is then installed on the upper portion of thefront leg rod member (21). Two long leg members (30) are connected andmounted pivotally to each other via a pin hole (301) in the centralportion thereof to form the x-shape structure. The pin holes (302) ofboth ends of the long leg members (30) are respectively fixed to thepivot bracket (121) of the base cap (12) and the pivot bracket (141) ofthe receiving cap base (14) forming the front and rear side of the wholeframe structure. Two short leg members (40) are connected and mountedpivotally to each other via the pin hole (40) in the central portion toform another X-shape structure. The pin holes (401) of both ends of oneshort leg member (40) are respectively fixed with the pivot bracket(131) on the receiving cap (13) of the rear leg rod unit (10) and withthe pivot bracket (221) on the receiving cap base (22) of the front legrod unit (20). The pin holes (402) of both ends of another short legmember (40) are respectively fixed to the pivot bracket (141) on thereceiving cap base of the rear leg (14) and to the pivot bracket (131)on the receiving cap (13) of the front leg rod unit (20) forming theright and left side of the whole frame structure. The fixing cap (52) isengaged with the protrusion (511) on the main shaft (51) forming thestructure of the movable armrest unit (50).

When unfolding the frame, the rear leg rod members (11) and the frontleg rod members (21) are pulled outward, and the corners of the seat matare respectively installed with two rear leg rod members (11) and twofront leg rod members (21). The fixing caps (52) of the two movablearmrest units (50) are engaged with two rear leg rod members (11) whilethe groove (513) in the receiving cap base of the front leg (22) isinstalled with the top of the front leg rod member (21) to form thechair frame structure and the unfolded position.

When folding the frame structure, the receiving cap base of the frontleg (22) is took off from the front leg rod member (21), the main shaft(51) is pressed downward, the fixing clip (514) on the receiving capbase of the front leg (22) is clipped and fixed to the rear leg rodmember (11), then the front leg rod member (21) and the rear leg rodmember (11) are together folded inward. Since the receiving cap (13) islocked up and immobile, therefore the receiving cap base of the rear leg(14) and the receiving cap base of the front leg (22) are forced liftedupward and the cross-shaped long and short legs is formed into I-shapefrom X-shape to complete the folding action.

Please refer to FIG. 6, the second example of the preferred embodiment.One end of the cross-shaped long leg members (30) are respectivelyinstalled on the receiving cap of the rear leg (14) and the receivingcap of the front leg (22); another end of the cross-shaped long legmembers (30) are installed on the base caps (12). One end of thecross-shaped short leg members (40) are respectively installed on thereceiving cap of the rear leg (10) and the receiving cap of the frontleg (20); another end of the cross-shaped short leg members (40) areinstalled on the receiving caps (13). The receiving cap of the front leg(22) and the receiving caps of the rear legs (14) are respectivelymounted and fixed to the upper portion of the front leg rod member (21)and the rear leg rod member (11); meanwhile the receiving caps (13) arerespectively installed movably on the front leg rod member (21) and therear leg rod member (11). The cylinder sheath (122) of the base cap (12)is extending from its top capable of being moved upward and downwardalong the front leg rod member (21) and the rear leg rod member (11).When folding the frame structure, the base caps (12) are forced movingdownward since the receiving cap of the front leg (22) and the receivingcap of the rear leg (14) are immobile, and the cross-shaped long legmember (30) along with the cross-shaped short leg member (40) are forcedto move inward to complete the folding action.

Please refer to FIG. 7, the third example of the preferred embodiment.One end of the cross-shaped long leg members (30) are respectivelyinstalled on the receiving cap of the front leg (22) and the receivingcap of the rear leg (14); another end of the cross-shaped long legmembers (30) are respectively installed on the base caps (12). One endof the cross-shaped short legs members (40) are respectively installedon the base caps (12) and another ends are respectively installed on thereceiving caps (13) which are mounted and fixed to the middle portion ofthe front leg rod member (21) and the rear leg rod member (11). The basecaps (12) are installed movably on the lower portion of the front legrod member (21) and the rear leg rod member (11). The cylinder sheath(122) of the base cap (12) is extending from its top and capable ofmoving upward and downward along the front leg rod member (21) and therear leg rod member (11). When folding the frame structure, the basecaps (12) are forced moving downward since the receiving cap (13) areimmobile, and the cross-shaped long leg member (30) along with thecross-shaped short leg member (40) are forced to move inward to completethe folding action.

1-6. (canceled)
 7. A foldable chair frame comprising: a pair ofcross-shaped long leg members and short leg members being installed withfixing holes respectively at the central part and the ends thereof, saidcross-shaped long leg members being connected pivotally to each othervia pin holes at the central part forming X-shape structure and beinginstalled between a pair of front leg rod member and rear leg rod memberforming the front and rear side of a frame structure; and saidcross-shaped short leg members being connected pivotally to each othervia said pin holes at the central part forming X-shape structure andbeing installed between said rear leg rod members and said front leg rodmembers forming smaller area of left and right side of said framestructure and becoming a rectangular shape suitable for sitting in whensaid frame structure being in unfolded position; one end of saidcross-shaped long leg members being installed on a receiving cap base ofthe rear leg or said receiving cap base of the front leg, and the otherend being correspondingly installed on a base cap at the bottom of saidrear leg rod members or on a base cap at the bottom of said front legrod members; one end of said cross-shaped short leg members beinginstalled on said receiving cap base of the rear leg or said receivingcap base of the front leg, and the other end of said cross-shaped shortleg members being correspondingly installed on said receiving caps atthe bottom of said rear leg rod members or on said receiving caps at thebottom of said front leg rod members.
 8. The foldable chair frameaccording to claim 7, wherein said receiving caps are respectivelymounted and fixed to the middle portion of said rear leg rod members andfront leg rod members; said receiving cap base of the front leg and saidreceiving cap base of the rear leg being respectively installed movablyat the upper portion of said rear leg rod members and said front leg rodmembers; a cylinder sheath extending from the bottom of said receivingcap base of the front leg and being installed thereon.
 9. (canceled) 10.The foldable chair frame according to claim 7, wherein said receivingcap base of the front leg and said receiving cap base of the rear legcan also be respectively fixed to the upper portion of said front legrod unit and said rear leg rod unit; said receiving caps beingrespectively installed movably on and capable of moving upward anddownward along said front leg rod member and said rear leg rod member; acylinder sheath extending from the bottom, for engaging with the bottomof said front leg rod members and said rear leg rod members and capableof moving upward and downward along said front leg rod members and saidrear leg rod members.
 11. The foldable chair frame according to claim 7,one end of said cross-shaped long leg members being installed on saidreceiving cap base of the rear leg and said receiving cap base of thefront leg, and the other end being installed on said base cap; one endof said cross-shaped short leg members being installed on said basecaps, and the other end of said cross-shaped short leg members beinginstalled on said receiving caps.
 12. The foldable chair frame accordingto claim 10, wherein said receiving caps are mounted and fixed to themiddle portion of said front leg rod members and said rear leg rodmembers; said base caps being respectively installed movably on thelower portion of said front leg rod member and said rear leg rod member;said cylinder sheath extending from the top of said base cap beinginstalled on and capable and quick of moving upward and downward alongsaid front leg rod members and rear leg rod members.